include/asm-ppc/spinlock.h

   1 #ifndef __ASM_SPINLOCK_H
   2 #define __ASM_SPINLOCK_H
   3
   4 /* Simple spin lock operations.  There are two variants, one clears IRQ's
   5  * on the local processor, one does not.
   6  *
   7  * We make no fairness assumptions. They have a cost.
   8  */
   9
  10 typedef struct {
  11         volatile unsigned long lock;
  12         volatile unsigned long owner_pc;
  13         volatile unsigned long owner_cpu;
  14 } spinlock_t;
  15
  16 #define SPIN_LOCK_UNLOCKED      (spinlock_t) { 0, 0, 0 }
  17 #define spin_lock_init(lp)      do { (lp)->lock = 0; } while(0)
  18 #define spin_unlock_wait(lp)    do { barrier(); } while((lp)->lock)
  19
  20 extern void _spin_lock(spinlock_t *lock);
  21 extern void _spin_unlock(spinlock_t *lock);
  22 extern int spin_trylock(spinlock_t *lock);
  23
  24 #define spin_lock(lp)                   _spin_lock(lp)
  25 #define spin_unlock(lp)                 _spin_unlock(lp)
  26
  27 #define spin_lock_irq(lock) \
  28         do { __cli(); spin_lock(lock); } while (0)
  29 #define spin_lock_bh(___lk) do { local_bh_disable(); spin_lock(___lk); } while(0)
  30
  31 #define spin_unlock_irq(lock) \
  32         do { spin_unlock(lock); __sti(); } while (0)
  33 #define spin_unlock_bh(___lk) do { spin_unlock(___lk); local_bh_enable(); } while(0)
  34
  35 #define spin_lock_irqsave(lock, flags) \
  36         do { __save_flags(flags); __cli(); spin_lock(lock); } while (0)
  37 #define spin_unlock_irqrestore(lock, flags) \
  38         do { spin_unlock(lock); __restore_flags(flags); } while (0)
  39
  40 extern unsigned long __spin_trylock(volatile unsigned long *lock);
  41
  42 /*
  43  * Read-write spinlocks, allowing multiple readers
  44  * but only one writer.
  45  *
  46  * NOTE! it is quite common to have readers in interrupts
  47  * but no interrupt writers. For those circumstances we
  48  * can "mix" irq-safe locks - any writer needs to get a
  49  * irq-safe write-lock, but readers can get non-irqsafe
  50  * read-locks.
  51  */
  52 typedef struct {
  53         volatile unsigned long lock;
  54         volatile unsigned long owner_pc;
  55 } rwlock_t;
  56
  57 #define RW_LOCK_UNLOCKED (rwlock_t) { 0, 0 }
  58
  59 extern void _read_lock(rwlock_t *rw);
  60 extern void _read_unlock(rwlock_t *rw);
  61 extern void _write_lock(rwlock_t *rw);
  62 extern void _write_unlock(rwlock_t *rw);
  63
  64 #define read_lock(rw)           _read_lock(rw)
  65 #define write_lock(rw)          _write_lock(rw)
  66 #define write_unlock(rw)        _write_unlock(rw)
  67 #define read_unlock(rw)         _read_unlock(rw)
  68
  69 #endif /* __ASM_SPINLOCK_H */